Railway signaling system



Dec. `8', 1942.

' w. wgHARTIzELL RAILWAY SIGNALING SYSTEM Filed May 8,- 1941 .d ad.

Patented Dec. 8, 1942 UNITED STA-resa PATENT General ARailwaySignal Company; Rocl'e'strj Application Mayes, 1941, sentiva-392,465

claims: (c1. 24652) This invention relates n.in general `to a .way-l side signalingsystem for' railways, .and-'has more# particular reference to means for providing; added.-` safeguards f againstk accident and simplified' means for carrying, such safeguardsinto effect.,

One of the objectsof the present' inventiontisfl to` provide means of a: simple nature cooperating; with a two-arm wayside Vsignal-which iszeective to yshift thelthen controler-the upper arm',k toV the lower arm, Awhile disconnecting *the 'controlJ of the lower arm, inthe'event i-ofiailurebfthe? upper arm.

means for placing the lower armsi'gnal-at dangerl if "ther control means for `the'nipperarm l should become inoperative;A

Further. objects,`vv purposes and characteristic 2 features ofthi'sl inventions-Will appear '-a's the descriptionprogresses, reference being v'made itofthe accompanying drawing,v showing inY 'a wholly Hdia;-

grammatic manner, Yand no-Slway `'whatsoeverfv in. a *limitingl sense' one form which? the in'vnl tion can assume.Y In the drawing-- Figgvl is a-wholly schematic representationoff one form of: the present 'invention Fig." 2 is va table showir`1g-th`e varicus signal aspects obtained under various conditions. t

Referring nowftof-the drawingg-'and vfirst toFig' 1,- there is'here represented astretch'of1"single track dividedi-in'to isolated '-sig'nal-'sec'tions 3, SFI,

S-and I I by usual-insulating joints 'I2-with sectinf II yentering an interlccking'plant,-orincludig'al' turnout, such as I3? whereby this signalsecti'on isan approach toranffadde'd traiclfhazardQ The signal sections are supplied Awith track vbatteries f' and track relays in the usual manner, althougl-i",A except vin special instances; as will-appear below, these devices haveA not beensho'wn'on'the drawing inthe interest; of clarity."

At the entrance to each signal sectionf is a way side signal suchas the signal 5G, having-`an u'pperarmAY anda lowerlar-rnB-.- These separate" arm" signals are representedY asbeingfoolorfli'ght* signals of the type kno-wnasfthe'fS'Al signalgsuch,

for instance as shown inthe-O.` S. Fe'ldrpatenty No. 2,097,785-, granted November 2,1 1937?' Each signal of this type has a' singlslig'ht source with 'l a spectacle movablein front of -thelight source having different colored roundels; as red, yellow and "green, with almechanism'V for movingfthe spectacle" relatively toltheilightrsource': If the signal: mechanism lbe energized with Jc1.1r1"ent--=of one polar-ity,- which may be termednorma-l polar-l ityffthe signahaspe'ct 1 is vgreen, ifffener'gizedf withy -nisrn EGAA for the-uppenarm/,'andfa-Llightsourc termed reverse polaritw A theVP signal aspectY is ye1low, whileI :if :thea-mechanism aber deenergized-J the Y signal-f aspect t is redr The signals at-f' the entrances to 1 the "other-y sections shown-have mot l been represented in theffdrawingain the-interest of simplicity," but v can bero-inthe: samen-general type Vas thatl represented atfthe': entrance-to lsection 5,1 although some ofthef signals .may include *s a diierent number yof armsfas three, forY example`V The vdirection `of' traino-finl this system yis conf-v `sidered lto bei easterly .-asindicated Vby arrow; I 4:'

The signalffSG is shown=--somewhatfini-ldetail in-the'wcircuit diagramcofwthis g'ure;L It-.com prises'a light source I 5, vvand anoperating :fmecha-y I6 rand 'anvoperating mechanismf SGB for i therv lower..l arm. Inl series wit'hffthe two .lightv sources f are adjustable current limiting means:H I'I "and |851 The I energyffor the lightfsources.. l-isl normally yfrom an alternatingccurrent sourfce hav-ing 'termi-c re'ctierRecf. connected acrc'ssftlie lo'werlwinding ThelupperlE windin loffs= lightroutfrrelay'f LOR' f is energizedlwhenthere islfnowoccupancy'fiofitrac sectionf3 Ibyfa circuit including-:contact 'ngeri A and r-ontfpoin of anapproacherrergy relayAER which-initurniis:energizedilthrougrifaicircuit initrent limiting means I'I, wire 29, contact linger 20 and front point of relay POR, and wire 30 to the other side of the secondary of transformer TR. Thus it can be seen that the lower winding of relay LOR is in series with the light source of the upper arm of signal G and thus this winding becomes deenergized if the signal lament fails for any reason whatsoever.

The light source of the lower arm of signal 5G has an energizing circuit which includes the secondary of transformer TR, etc., as in the cire cuit traced just above, up to the wire 25, and thencethrough a branch circuit including wire 3l, lamp I S, and current limitingvmeans I8, to wires 28 and 29 of the circuit traced just above.

Thus, when the approach energy relay has re' leased, the signal light sources and the lower winding of relay LOR are all normallyfenergized by alternating current. Should the source of alternating current fail for any reason, power-off relay POR releases whereby the direct current source of energy is substituted for the alternating current source, and the signal light sources and the lower winding of relay LOR are then energized with direct'current. Y

yIt should be noted that rectier Rec. is poled as to oppose the ow of this direct current through it, whereby to prevent shunting. the direct current `away from lower winding LW. When the lower winding'LWY is energized by alternating current, however, only one-half of each cycle of alternating current is shunted out by the rectier, the other-half being blocked and'.

thus passing through the relay lower winding `so thatthe lowerwinding is energized by pulsating direct currentso as to hold Vup tightlyon alternating current and prevent any failure of operation or chattering.

:Upon light-out relay. LOR having its `upper winding deenergized, the decay. of iiux in the common core induces a voltage which sends a current through the lower winding in a direction to readily pass through the rectifier, whereby to make the relay slow to release. Relay LOR need notinclude any short-circuited copper band, orV

lthe like, to make it. slow torelease since the rectifier not only serves vto permit the relay to hold up readily and certainly on alternating current but `also imparts necessary slow release characteristics necessaryin therelay .for reasons to appear below.4

The upper armY signal mechanism 5GA is energizedfrom a .direct current .source through a circuit including contact; finger 33 and front point of a relay 'IGBGR contact linger 5T and front point, contact finger 34 and front point of relay LOR, the mechanism SGA and contact nger 35 and -front point of relay IGBGR These signal 5G and is energized when the upper arm contact ngers 33 and 35 constitute a part of a pole. changer whereby to energize the signalA mechanism with current` of either normal or reverse polarity, dependent upon whether the controlling relay be energized or deenergized..

This relay 'IGBGP is a relay which repeats the green indication of the signal 1G at the entrance to section 'I. Thus, this relay is deenergized when the lower arm of signal 'IG is giving either a red or a yellow indication, and is energized when this signal arm is giving a green indication.

AThe signal mechanism 5GB of the lower arm of signal 5G is` energized from la source of direct current through a circuit including contact linger A35 and front point of a relay 'IGAYGR contact linger 3'I and iront point or a relay of signal 5Gdisplays yellow or green and is deenergized when it displays red. These signal repeater relaysare Well known in the art, as is shown, for example, in the patent to S. M. Day,

No. 2,105,905, granted January 18, 1938.

If, for any reason, as perhaps, because of failure of the filament of lamp I5 of the upper arm of the signal 5G, relay LOR releases, its contact iingers 38 and 39 will leave their front points, and thus cut the lower arm signal mechanism oirfrom its control circuit as described above, and by making up their back points will connect it through wires 4I and 42 to the `control circuit for the upper arm mechanism by reason of contact finger making up its back point. The movement. of contact finger 34 from its front point, of course,

causes deenergization of the signal mechanism of the upper arm of the signal whereby to cause its spectacle to move to its red position.` Since,..

however, the light source has failed, the signal will be a dark signal.

Assumenow that a train, moving in an easterly; direction enters section 3. Signal 5G has both` arms positioned for displaying a green indication, or green over green, that is, G/G. v

Release, however, of the track relayfor. .this

section 3 opens the energizing circuit for relay AER at `contact finger 3T and front point, whereby contact ngers 2| and 24 of the approach' energy relay release. The release of contact nger 2| deenergizes the light-out relay LOR but since this relay is slow to release due to the rectier bridged across it, before it releases the making up of contact nger 24 with its backpoint, energizes the lower windngLW of this relay in series with the light source I5 so that Yrelay LOR normally does not release. Also in multiple with the light-out relay and the light source l5, the light source. I 5 for the lower arm of signal 5G is energized. Should the alternating current source fail for any reason, power-oir relay POR will shift the circuits involved to the reverse direct current source of energy.

As the train occupying Vtrack section 3 ad# l .ances through the various sections 5, 1, 9 and il, signal 5G displays various indications as set forth in Fig. 2.

As shown in Fig. 2, with section 5 occupied, the signal 5G displays an R/R indication, since the release of the track Yrelay for this section deenergizes the upper arm mechanism at contact linger 5T and front point and with ,they upper arm displaying an R indication, the repeater relay of this mechanism 5GAYGP releases to thus deenergize the lower arm mechanism.

Upon the train occupying section 'I and vacating section 5, signal 'IG displays an R/R indication. As a result, signal 5G displays a Y/R indication since the release of relay rIGBGP in the control circuit for the upper arm of signal 5G puts reverse polarity on the mechanism to give a Y indication while the release of the repeaterl 34 leaving Yits front point and relay for the upper arm of signal 1G, that is, relay 1GAYGP deenergizes the lower arm mechanism of signal 5G to produce an R indication.

In the same way, on the train vacating section 1 and occupying section 9, signal 5G gives a Y/G indication. Upon the train vacating section 9 and occupying section Il signal 5G gives a G/G indication.

It can be realized that, should the filament of the upper arm of signal-5G, for example, fail, a dark signal results. If this failure should occur when signal 5G is displaying its Y/G indication, the resulting signal would appear as a G indication, and this indication, more permissive than should be in force, will give insufficient braking distance for trains approaching signal 5G, with resulting possible danger. However, with the system as described above, upon the filament l5 failing, since the upper winding of the light-out relay LOR is deenergized, due to section 3 being occupied, and the relay depending for its energization upon its lower winding LW, which is in series with the light lament which has failed, the light-out relay releases. This shifts the control then existing for the upper arm of the signal, to the lower arm of the signal, and thus the lower arm of the signal changes from a G to a Y indication, while the upper arm is dark. As indicated in Fig. 2, this intended signal Y/G instead of becoming the more permissive signal aspect G, displays the aspect of a dark signal over a Y indication to constitute a more restrictive signal than the one that should have been in force.

Assume again that section l l is occupied whereby the signal 5G is displaying an aspect of G/G and a train approaching this signal enters track section 3. Further, assume that the control circuit for the upper arm of signal 5G fails to be effective for any reason, such, for example, as a broken wire or a failure of the source of energy, or the like. Upon such a failure, the upper arm of signal 5G displays an R indication and the repeater relay EGAYGP of this arm which has its contact 31 in the control circuit of the lower arm of this same signal, releases to deenergize the lower arm mechanism and cause it to display an R indication.

Thus, with the control circuit for the lower arm of the signal constituted as described above, such a failure as just referred to changes a signal aspect of G/G to a signal aspect of R/R which is a recognizable signal. If it were not for the provision of the repeater relay contact 31 in the lower arm control circuit, the upper arm would display an R indication while the lower arm would continue to display its G indication to give an unorthodox and confusing and possibly dangerous signal aspect of R/ G.

It should further be noted that, by employing the contact 31 of the repeater relay BGAYGP in the lower arm mechanism control circuit, an added contact on the track relay 5T is eliminated, and is replaced by a contact already available in the upper arm signal.

It is thus apparent that the various functions of safeguarding the wayside signaling system, as described above, against dangerous conditions arising, due to failure of lamp filaments and of mechanism control circuits, are accomplished in a very simple and economical manner. This is realized by employing a single double-wound relay LOR for the light-out function, and by employing a rectifier in connection with this relay, which not only imparts slow release characteristics to the relay as a whole, but fits the lower winding of the relay to be efficiently and dependably energizable by either alternating or direct current.

The above rather specific description of one form which this invention can assume is given solely by way of example, and is not intended in any manner whatsoever in a limiting sense. It is to be understood that various modifications, adaptations and alterations may be applied to meet the requirements of practice without in any manner departing from the spirit and scope of the invention, except insofar as limited by the appended claims.

Having described my invention, I now claim:

1. In a railway signal system, in combination, a signal comprising an upper and a lower arm, each of which includes a light source, an operating mechanism, a control circuit for the light source, and a control circuit for the mechanism,

means controlling each mechanism control circuit in accordance with traffic conditions, a lightout relay having two windings, an energizing circuit for one of the windings, an energizing circuit for the other winding including one of the light sources in series, means controlled by approaching traffic for deenergizing said one winding and energizing said .other winding and the light sources, and means effective,` upon failure of said one light source, to shift the control of the mechanism of said one light source to the other mechanism, and to disconnect said other mechanism from its own control circuit.

2. In a railway signal system, in combination, a signal comprising an upper and a lower arm, each of which includes a light source, an operating mechanism, a control circuit for the light source, and a control circuit for the mechanism, means controlling each mechanism control circuit in accordance with traffic conditions, a lightout relay having two windings, an energizing circuit for one of the windings, an energizing circuit for the other winding including one of the light sources in series, means controlled by approaching traffic for deenergizing said one winding and energizing said other winding and the light sources, means effective upon failure of said one light source to shift the control of the mechanism of said one light source to the other mechanism and to disconnect said other mechanism from its own control circuit, and a rectifier bridged across said other winding.

3. In a railway signal system, in combination, a signal comprising an upper and a lower arm, each of which includes a light source, an operating mechanism, a control circuit for the light source, and a control circuit for the mechanism, means controlling each mechanism control circuit in accordance with trafc conditions, a lightout relay having two windings, an energizing circuit for one of the windings, an energizing circuit for the other winding including one of the light sources in series, means controlled by approaching trafc for deenergizing said one winding and energizing said other winding and the light sources, means effective upon failure of said one light source to shift the control of the mechanism of said one light source to the other mechanism and to disconnect said other mechanism from its own control circuit, a rectier bridged across said other winding, a source of alternating current in the energizing circuit for the other winding, a stand-by source of direct current, and means to replace the alternating current source by the direct current source upon failure of the alternating current source.

4. In a railway signal system, in combination a signal comprising an upper and a lower arm, each of which includes a light source, an operating mechanism, a control circuit for the light source, and a control circuit for the mechanism, means controlling each mechanism control circuit in accordance with traic conditions, a lightout relay having two windings, an energizing circuit for one of the windings, an energizing circuit for the other winding including one of the light sources :'n series, means controlled by approaching traiic for deenergizing said one winding and energizing said other winding and the light sources, means eiective, upon failure of said one lightJ source, to shift the control of the mechanism of said one light source to the other mechanism and to disconnect said other mechanism from its own control circuit, a rectier bridged across said other Winding, a source of alternating current in the energizing circuit for the other winding, a stand-by source of direct current, and means to replace the alternating current source by the direct current source upon failure of the alternating current source, the rectier being poled to block flow of direct current from said replacement source.

5. In a railway signal system, in combination,

a, signal comprising an upper and a lower arm, each of which includes a light source, an operating mechanism, a control circuit for the light source, and a control circuit for the mechanism, means controlling each mechanism control cir,- cuit in accordance with trafc conditions, a lightout relay having two windings, an energizing circuit for one of the windings, an energizing circuit for the other winding including one of the light sources in series, means controlled by approaching trafc for successively deenergizing said one winding and energizing said other winding and the light sources, means effective, upon failure of said one light source, to shift the control of the mechanism of said one light source to the other mechanism and to disconnect said other mechanism from its own control circuit, a rectier bridged across said other Winding, a. source of alternating current in the energizing circuit for the other Winding, a stand-by source of direct current, and means to replace the alternating current source by the direct current source upon failure of the alternating current source, the rectier being poled to block flow of direct current from said replacement source and to make the relay slow to release upon deenergization of said one winding.

WILLIAM W. HARTZELL. 

